1. Field of the Invention
The present invention relates to a mobile communication system, and more particularly, to technology that may transmit control information from a terminal to a base station.
2. Description of the Related Art
An uplink of a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) system and an LTE-Advanced system may transmit a single carrier based on a single carrier-frequency division multiple access (SC-FDMA) scheme. Accordingly, when a terminal is assigned with an uplink data channel, control signaling may occur. The control signaling may be time division multiplexed and thereby be mapped to each SC-FDMA symbol. A data transmission channel for transmitting an uplink transport block is referred to as Uplink Shared Channel (UL-SCH). To transfer control information used for transmitting an uplink transmission channel and a downlink transmission channel, uplink control signaling may be performed with respect to Hybrid Automatic Request (HARQ)-Acknowledgment (ACK), channel state information, and the like. Uplink control signaling defined in the existing 3GPP LTE system may follow as:
HARQ-ACK corresponds to very important information in a downlink operation to feed back, to a base station, a detection result with respect to a downlink transport block received by a terminal. The base station may be aware of a point in time when HARQ-ACK is to be received based on a point in time when the downlink transport block is transmitted. However, when the terminal does not detect downlink scheduling information, HARQ-ACK may not be transmitted. When a data rate matching pattern of a data channel varies depending on HARQ-ACK, the data channel may not be successfully decoded. Accordingly, HARQ-ACK may be transmitted by puncturing a portion of encoded data channel bits.
The channel state information may include channel quality information (CQI), a precoding matrix indicator (PMI), and a rank indicator. Only when the base station requests CQI for uplink scheduling information, the channel state information may be transmitted using the data channel. As described above, the base station may need to be accurately aware of a point in time when the channel state information needs to be transmitted. Accordingly, in the case of data rate matching of the data channel, a magnitude of the channel state information may be included. When the channel state information is multiplexed with the data channel and thereby is transmitted, a code rate may be enhanced.